Extended Unifrontal craniotomy for midline anterior cranial fossa meningiomas: A better shot at preservation of neurovascular structures.

Numerous surgical approaches have been described for the resection of anterior cranial fossa meningioma. The common problems associated with these approaches are excessive brain retraction, injury to neurovascular structures, transection of superior sagittal sinus (SSS), and a higher risk of new-onset anosmia. The authors describe a unilateral extended frontal approach with the aim to minimize brain handling without the need for SSS transection and possibly better olfaction preservation. METHODS: Thirteen patients with anterior cranial fossa meningioma were operated on using the novel technique of unilateral extended frontal skull base approach. The clinical presentation, radiological studies, intraoperative findings, and outcome at follow-up were recorded. RESULTS: Gross total tumor resection could be achieved in 12 out of 13 patients. At least one of the olfactory tracts could be anatomically preserved in all patients, and superior sagittal sinus was preserved in all patients. Functional olfaction preservation was achieved in 8 patients. No patient developed new-onset anosmia. CONCLUSIONS: The extended unilateral frontal approach is a viable and reliable alternative for extended bifrontal technique for the resection of large midline anterior cranial fossa meningiomas with avoidance of SSS ligation, decreased brain handling with better olfaction preservation while achieving comparable tumor resection and acceptable cosmetic outcomes.

A Novel Pedicle Screw Design with Variable Thread Geometry: Biomechanical Cadaveric Study with Finite Element Analysis.

BACKGROUND: Pedicle screw fixation provides one of the most stable spinal constructs. Their designs together with osseous characteristics have been known to influence the screw-bone interplay during surgical maneuvers and thereafter the fusion process. Various technical modifications to enhance screw performance have been suggested. This study evaluated the pull-out strength and axial stiffness of a novel pedicle screw design with variable thread geometry and pitch. METHODS: The newly designed triple threaded pedicle screw is tapered, and has unique out-turned flanges to hold the cancellous bone and a finer pitch at its distal and proximal end to engage the cortical bone. Five lumbar and 4 lower thoracic cadaveric vertebrae were divided into hemivertebrae. A standard cancellous pedicle screw and the newly designed pedicle screw were inserted into each hemivertebra. Axial stiffness and peak pull-out force between the screw types were compared; a finite element analysis was also performed to additionally compare the pull out under toggle forces. RESULTS: In cadaveric study, the axial stiffness of the new screw was significantly better than that of the standard screw. However, the peak load between the screws was not statistically different. Finite element analyses suggested lesser stress at bone-implant interface for the new screw along with better axial stiffness under both co-axial and toggle forces. CONCLUSIONS: Our novel pedicle screw design with variable thread geometry demonstrates greater axial stiffness compared with the standard screws, and therefore is likely to withstand a greater surgical manipulation.

Carotid cavernous fistula: Redefining the angioarchitecture.

OBJECTIVE: Numerous classification schemes have been used for carotid cavernous fistula (CCF), each describing some aspect of the disease process but none of them provides a complete description of the fistula including its clinical features, natural history, arterial and venous architecture. METHODS: Retrospective clinical and radiological review was done for all the patients diagnosed with CCF and treated at our institute. The CCF were classified according to the proposed API-ACE classification along with Barrow and Thomas classification. RESULTS: Overall 28 patients (M=21, F=7) were diagnosed and treated during the 6-year period. 89.2% of CCF developed following an episode of head injury. Orbital symptoms were the most common presenting complaints. Barrows type A was the most predominant subtype (n=24) and most of the patients (n=23) demonstrated decreased ipsilateral carotid filling. Combined anterior and posterior drainage pattern was the most common drainage pattern and anterior drainage was more commonly observed than posterior drainage. CONCLUSIONS: API-ACE classification helps to better understand and classify the angioarchitecture of CCF which could help better understand the clinical manifestations and guide in appropriate endovascular approach selection for treatment.

The Relationship between Contralateral Suppression of Transient Evoked Otoacoustic Emission and Unmasking of Speech Evoked Auditory Brainstem Response

Abstract Introduction Several studies have shown that efferent pathways of the auditory system improve perception of speech-in-noise. But, the majority of investigations assessing the role of efferent pathways on speech perception have used contralateral suppression of otoacoustic emissions as a measure of efferent activity. By studying the effect of efferent activity on the speech-evoked auditory brainstem response (ABR), some more light could be shed on the effect of efferent pathways on the encoding of speech in the auditory pathway. Objectives To investigate the relationship between contralateral suppression of transient evoked otoacoustic emission (CSTEOAE) and unmasking of speech ABR. Methods A total of 23 young adults participated in the study. The CSTEOAE was measured using linear clicks at 60 dB peSPL and white noise at 60 dB sound pressure level (SPL). The speech ABR was recorded using the syllable /da/ at 80 dB SPL in quiet, ipsilateral noise, and binaural noise conditions. In the ipsilateral noise condition, white noise was presented to the test ear at 60 dB SPL, and, in the binaural noise condition, two separate white noises were presented to both ears. Results The F0 amplitude of speech ABR was higher in quiet condition; however, the mean amplitude of F0 was not significantly different across conditions. Correlation analysis showed a significant positive correlation between the CSTEOAE and the magnitude of unmasking of F0 amplitude of speech ABR. Conclusions The findings of the present study suggests that the efferent pathways are involved in speech-in-noise processing.

The Relationship between Contralateral Suppression of Transient Evoked Otoacoustic Emission and Unmasking of Speech Evoked Auditory Brainstem Response.

Introduction Several studies have shown that efferent pathways of the auditory system improve perception of speech-in-noise. But, the majority of investigations assessing the role of efferent pathways on speech perception have used contralateral suppression of otoacoustic emissions as a measure of efferent activity. By studying the effect of efferent activity on the speech-evoked auditory brainstem response (ABR), some more light could be shed on the effect of efferent pathways on the encoding of speech in the auditory pathway. Objectives To investigate the relationship between contralateral suppression of transient evoked otoacoustic emission (CSTEOAE) and unmasking of speech ABR. Methods A total of 23 young adults participated in the study. The CSTEOAE was measured using linear clicks at 60 dB peSPL and white noise at 60 dB sound pressure level (SPL). The speech ABR was recorded using the syllable /da/ at 80 dB SPL in quiet, ipsilateral noise, and binaural noise conditions. In the ipsilateral noise condition, white noise was presented to the test ear at 60 dB SPL, and, in the binaural noise condition, two separate white noises were presented to both ears. Results The F0 amplitude of speech ABR was higher in quiet condition; however, the mean amplitude of F0 was not significantly different across conditions. Correlation analysis showed a significant positive correlation between the CSTEOAE and the magnitude of unmasking of F0 amplitude of speech ABR. Conclusions The findings of the present study suggests that the efferent pathways are involved in speech-in-noise processing.

Clinical utility of serum glial fibrillary acidic protein in glial neoplasm.

Background: Glial fibrillary acidic protein (GFAP) is a member of the cytoskeletal protein family and is widely expressed in astroglial and neural stem cells, also in glial tumors such as astrocytoma and Glioblastoma (GBM). Increased GFAP expression and disruption of the blood-brain barrier are the characteristic features of GBM. Higher serum GFAP levels can help differentiate GBM from GBM mimics (such as primary central nervous system lymphoma, metastasis, or demyelinating lesions). Methods: This prospective study was carried out in a tertiary care center in the department of neurosurgery on newly diagnosed glioma patients who underwent surgery from January 2018 to July 2019, excluded patients with history of the previous surgery for glioma, traumatic brain injury, and ischemic or hemorrhagic stroke. The blood sample was obtained at admission before undergoing invasive procedure. Pathological examination of the tumor biopsy sample was carried out using classical hematoxylin-eosin and immunohistochemical staining. All statistical analyses were performed using SPSS version 24.0. Results: The mean preoperative tumor volume was 40 cm3 (range 17.19-65.57 cm3; standard deviation [SD] = 9.99 cm3) which showed 98.25% mean reduction in volume postsurgery (mean tumor volume = 0.7 cm3; SD = 0.19 cm3). Preoperative serum GFAP measurements show higher levels (spearman's rho coefficient = 0.610 with P = 0.000) with increasing grade of tumor. GFAP levels also demonstrated higher value with increasing preoperative tumor volume. Conclusion: Increasing serum GFAP levels in the preoperative period correlate with higher tumor grade, especially grade III and grade IV tumors. The serum GFAP levels showed relation to tumor volume, both before and after surgery.

Curious Case of Atypical Hangman's Fracture: C2-C3 Listhesis without Pars Fracture.

Traumatic spondylolisthesis of axis or hangman's fracture is the second most common C2 vertebra injury. We present a report of a young man presenting with a history of fall from height with C2 to C3 spondylolisthesis without any evidence of injury to pars interarticularis but with associated injury to capsular ligament of facet joint along with posterior spinous ligamentous injury. The patient underwent intraoperative reduction in listhesis with posterior screw fixation. The patient showed uneventful postoperative course with neurological improvement at 6-week follow-up. Hangman's fracture refers to a diverse group of injury in which the soft tissue injury has an equally important part to play as the bone fracture.